Use the flour, water, sugar, oil, baking powder, and rum to knead a very soft dough. Divide it into 2 parts.
Roll out 1 half along the bottom of the baking tray (or form). Smear it with plenty of marmalade of your choice, sprinkle the top with chopped walnuts. Grate the apples, mix them with the sugar, cinnamon and breadcrumbs and put them to serve as the filling for the pie.
Knead the remaining half of the dough with flour. Roll it out, cut it into strips and arrange them on top of the pie. Put the apple pie to bake in a moderate oven.